var makeError = require("make-error");

var CustomError = makeError("CustomError");

// Parameters are forwarded to the super class (here Error).
throw new CustomError("a message");

function CustomError(customValue) {
  CustomError.super.call(this, "custom error message");

  this.customValue = customValue;
}
makeError(CustomError);

// Feel free to extend the prototype.
CustomError.prototype.myMethod = function CustomError$myMethod() {
  console.log("CustomError.myMethod (%s, %s)", this.code, this.message);
};

//-----

try {
  throw new CustomError(42);
} catch (error) {
  error.myMethod();
}

var SpecializedError = makeError("SpecializedError", CustomError);

throw new SpecializedError(42);

import { BaseError } from "make-error";

class CustomError extends BaseError {
  constructor() {
    super("custom error message");
  }
}